(1) Field of Invention
The invention relates to the removal of undesirable materials and ash from used or otherwise contaminated motor oil. The invention also relates to avoidance of environmental problems associated with disposal of heavy metal salts, and other persistent pollutants contained in used motor oil, by dumping the oil into the aquifers of landfills, sludge ponds, or storage drums, which are, themselves, capable of deterioration. (U.S. Patent class/subclass: 208/179, /180, /181, /182, /183, /184, /251, /289 and /283).
(2) Utility of the Invention
Improvement of used motor oil by removal of degraded components and other contaminants can provide reclaimed and reusable motor oil, which is often formulated with some added amounts of detergent-inhibitor package or else blended as an inexpensive added basestock with new motor oil. Used motor oils, both with and without partial removal of contaminants and ash have been used as rust inhibitors for equipment and machinery, as well as added components for hydrocarbon fuels.
(3) Description of Prior Work
Reclaiming of used motor oil may be distinguished from re-refining in that no high temperature distillation of motor oil basestocks is involved. The process thus is usually less expensive than re-refining. In spite of the value of recovering lubricant basestocks, reclamation has been minimal because of attendant expense involved in collection of small amounts of oil drainings and their shipment to a central point. However, recent awareness of the public, to the threat of water pollution, by used motor oil has generated new incentives for reclamation.
Reclaiming motor oil normally involves treatment with a solvent containing an active purifying agent. Although motor oil of a purer nature is obtained, usually an appreciable amount of sludge is coproduced as the contaminated solvent by-product. This sludge must then be disposed of in some non-polluting fashion. Sometimes it is concentrated by relatively expensive flash distillation.
In U.S. Pat. No. 4,105,538, for example, Mattox adds a light paraffinic hydrocarbon fraction, along with a rather expensive amine. Subsequently, appreciable portions of heavy metal salts and other contaminants precipitate to the bottom as solids. Excess light paraffinic fraction and amine must then be removed, although, with some amines, if attention is paid to the motor oil application later used, some amine can practicably be left in the reclaimed product.
In U.S. Pat. No. 3,879,282, Johnson employs water containing phosphate salts, in a sealed autoclave at about 170 psig and 132.degree. C. (270.degree. F.). Substantial amounts of contaminants and ash precipitate in the water phase as insoluble metal phosphates. Johnson's preferred embodiment involves a specially constructed multistep facility employing preheaters, vigorously agitated pressure vessels, a phase separator, settlement tank, and filters. Gasoline and water remaining in the oil are removed by a flash distillation step. Recycled water is then purified sufficiently for recycle or else rigorously enough to be discarded into the environment. Filtration of the treated oil is carried out with silica gel in order to remove extraneous matter, especially tetraethyl-lead which is not removed by the prior treatment.
Petroleum refiners have been investigating means for processing reduced crudes, such as by visbreaking, solvent deasphalting, hydrotreating, hydrocracking, coking, Houdresid fixed bed cracking, H-oil, and fluid catalytic cracking. One or more approaches to the processing of reduced crude to form transportation and heating fuels is that described in copending applications, U.S. Ser. No. 904,216 (now U.S. Pat. No. 4,341,624); 904,217 (now U.S. Pat. No. 4,347,122); 094,091 (now U.S. Pat. No. 4,299,687); 094,277 (now U.S. Pat. No. 4,354,923) and 094,092 (now U.S. Pat. No. 4,332,673) which are herein incorporated by reference thereto.
In the operations of the above identified applications, a reduced crude is contacted with a hot regenerated catalyst in a short contact time riser cracking zone, the catalyst and products are separated instaneously by means of a vented riser to take advantage of the difference between the momentum of gases and catalyst particles. The catalyst is stripped, sent to a regenerator zone and the regenerated catalyst is recycled back to the riser to repeat the cycle. Due to the high Conradson carbon vlues of the feed, coke deposition on the catalyst is high and can be as high as 12 wt % based on feed. This high coke level can lead to excessive temperatures in the regenerator, at times in excess of 1400.degree. F. to as high as 1500.degree. F. which can lead to rapid deactivation of the catalyst through hydrothermal degradation of the active cracking component of the FCC catalyst (crystalline alumiosilicate zeolites) and unit metallurgical failure.